[CTest] Setup Python dependencies for benchmarks.

When a benchmark uses Python (REQUIREMENTS OGS_USE_PYTHON) and
there is a requirements.txt file in benchmarks project file
directory a Python virtual environment is created and dependencies
are installed during benchmark execution via ctest (inside the
build directory).

The PYTHONPATH environment variable of the benchmark test is set
to the virtual environment to mimic virtual environment activation.

Normally you would use

source .venv/bin/activate

but this is not possible when executing the benchmarks via ctest.

scripts/cmake/test/AddTest.cmake

@@ -73,7 +73,7 @@ function (AddTest)
     # --- Implement wrappers ---
     # check requirements, disable if not met
     if(${AddTest_REQUIREMENTS})
-        # message(STATUS "Enabling test ${AddTest_NAME}.")
+        message(DEBUG "Enabling test ${AddTest_NAME}.")
     else()
         set(DISABLED_TESTS_LOG "${DISABLED_TESTS_LOG}\nRequirement ${AddTest_REQUIREMENTS} not met! Disabling test ${AddTest_NAME}." CACHE INTERNAL "")
         return()
@@ -243,15 +243,21 @@ Use six arguments version of AddTest with absolute and relative tolerances")
         COMMAND ${CMAKE_COMMAND}
         -DEXECUTABLE=${AddTest_EXECUTABLE_PARSED}
         "-DEXECUTABLE_ARGS=${AddTest_EXECUTABLE_ARGS}" # Quoted because passed as list
-        -Dcase_path=${AddTest_SOURCE_PATH}             # see https://stackoverflow.com/a/33248574/80480
+        -DSOURCE_PATH=${AddTest_SOURCE_PATH}           # see https://stackoverflow.com/a/33248574/80480
         -DBINARY_PATH=${AddTest_BINARY_PATH}
         -DWRAPPER_COMMAND=${WRAPPER_COMMAND}
         "-DWRAPPER_ARGS=${AddTest_WRAPPER_ARGS}"
         "-DFILES_TO_DELETE=${FILES_TO_DELETE}"
-        -DSTDOUT_FILE_PATH=${AddTest_STDOUT_FILE_PATH}
         -P ${PROJECT_SOURCE_DIR}/scripts/cmake/test/AddTestWrapper.cmake
     )
     set_tests_properties(${TEST_NAME} PROPERTIES COST ${AddTest_RUNTIME})
+    if(EXISTS ${AddTest_SOURCE_PATH}/requirements.txt)
+        set(PYTHONPATH "${AddTest_BINARY_PATH}/.venv/lib/python${Python3_VERSION_MAJOR}.${Python3_VERSION_MINOR}/site-packages")
+        if(WIN32)
+            set(PYTHONPATH "${AddTest_BINARY_PATH}/.venv/Lib/site-packages")
+        endif()
+        set_tests_properties(${TEST_NAME} PROPERTIES ENVIRONMENT "PYTHONPATH=${PYTHONPATH}")
+    endif()
 
     if(TARGET ${AddTest_EXECUTABLE})
         add_dependencies(ctest ${AddTest_EXECUTABLE})

scripts/cmake/test/AddTestWrapper.cmake

@@ -4,24 +4,27 @@ foreach(FILE ${FILES_TO_DELETE})
     file(REMOVE ${BINARY_PATH}/${FILE})
 endforeach()
 
-# convert list to space delimited string
-set(CMD "${WRAPPER_COMMAND}")
-foreach(A ${WRAPPER_ARGS})
-    set(CMD "${CMD} ${A}")
-endforeach()
-
-set(CMD "${CMD} ${EXECUTABLE}")
-foreach(A ${EXECUTABLE_ARGS})
-    set(CMD "${CMD} ${A}")
-endforeach()
-string(STRIP "${CMD}" CMD)
+# Create Python virtual environment and install packages
+set(PIP .venv/bin/pip)
+if(WIN32)
+    set(PIP .venv/Scripts/pip.exe)
+endif()
+if(EXISTS ${SOURCE_PATH}/requirements.txt AND NOT EXISTS ${BINARY_PATH}/${PIP})
+    message(STATUS "Generating Python virtual environment...")
+    execute_process(
+        COMMAND virtualenv .venv
+        WORKING_DIRECTORY ${BINARY_PATH})
+endif()
+if(EXISTS ${SOURCE_PATH}/requirements.txt)
+    execute_process(
+        COMMAND ${PIP} install -r ${SOURCE_PATH}/requirements.txt
+        WORKING_DIRECTORY ${BINARY_PATH})
+endif()
 
-message(STATUS "running command generating test results:\ncd ${case_path} && ${CMD} >${STDOUT_FILE_PATH}")
 execute_process(
     COMMAND ${WRAPPER_COMMAND} ${WRAPPER_ARGS} ${EXECUTABLE} ${EXECUTABLE_ARGS}
-    WORKING_DIRECTORY ${case_path}
+    WORKING_DIRECTORY ${SOURCE_PATH}
     RESULT_VARIABLE EXIT_CODE
-    # OUTPUT_FILE ${STDOUT_FILE_PATH} # must be used exclusively
     OUTPUT_VARIABLE OUTPUT
     ERROR_VARIABLE OUTPUT
 )